why does my URL for my blog get changed when using marsedit?

hey,im new to all this blogging and so this might be a bit of a dumb question. I have a blog on www.blog.com and i have been posting there for a while. i wanted to link my livejournal account so that one blog post would be easily submitted to two blog sites. research online lead me to marsedit - which is a great tool.with my livejournal link up all is well and my posts go directly to my LJ account.with my blog.com account however, my url has been changed from http://craiglennox.blog.com to http://craiglennox.blog.com/?p=45.With the added ?p=45 it means that my original blog site hasnt been updated. anyone got any ideas where i am going wrong in linking up my blog.com account?